1. Field of the Invention
This invention relates to a process for producing a readily crystallizable arylenesulfide resin (hereinafter sometimes referred to as PAS) composition. More particularly, the invention relates to a process for producing a readily crystallizable PAS resin composition, which composition is characterized in that crystallization from its glass state and/or molten state is very rapid, in that it forms very fine spherulite structures, in that it has a high degree of crystallization, and in that it is very crystallizable and has other desirable characteristics.
2. Prior Art
The PAS resin represented by polyphenylenesulfide and the like has been used in varieties of industrial fields as engineering plastics having excellent heat resistance, flame retardance, chemical resistance, etc.
A PAS resin itself is a typical crystalline high-molecular resin, and it is necesary to increase its crystallization sufficiently and to provide the optimum crystalline state for it to exhibit its performances. Conventional PAS resins, however, have a disadvantage in that crystallization from their glass state or molten state is slow and coarse spherulites are formed.
In order to promote crystallization of crystalline polymers, it has been known to add to such polymers a so-called crystal-nucleating agent of talc or silica. In the case of PAS, however, use of such a nucleating agent was hardly effective. A method of influencing crystallization of PAS is disclosed in Japanese Laid-open Patent Application No. 78257/1984 Specification, which comprises adding to the PAS a water-soluble compound selected from an oxide or hydroxide of a metal of IA and IIA groups of the periodic table. This method, however, aims to further retard the melt crystallization velocity of the PAS. It is also disclosed in Japanese Laid-open Patent Application No. 152019/1983 to wash PAS with an inorganic acid or an organic acid such as acetic acid and benzoic acid or to add these acids to PAS so as to improve the thermal stability thereof.